The Oceano Dunes south of Arroyo Grande Creek reopened Thursday morning just in time for the Memorial Day holiday weekend.The area shut down in April after a federal judge ruled that California State Parks was violating the Endangered Species Act. The closure lasted while State Parks awaited a permit from the U.S. Fish and Wildlife Service."We've been working on that permit with the U.S. Fish and Wildlife Service for several years now, and we ju…